1. Field of the Invention
This invention relates to denture adhesives or stabilizers, and particularly to an improved anhydrous denture adhesive composition.
2. Description of the Prior Art
Traditionally, adherent powders used to secure dentures within the mouth were prepared from such materials as finely powdered natural gums, i.e., karaya, acacia or tragacanth gum. These materials have the particular property of swelling to many times their original volume upon the addition of water to form a gelatinous or mucilaginous mass. Denture adhesive powders may be a combination of one or more natural gums, generally flavored with pleasant tasting volatile oils. Many other additives may also be included, such as antiseptics, stabilizers, bactericides, special deodorants, plasticizing agents, fillers, coloring agents, and the like.
Cream forms of the denture adherent, prepared from finely ground particles of the natural gums dispersed in a cream base, are also available and may be used instead of the powder compositions. In any event, when wet with water, the natural gum in either the cream or powder formulation, expands to become a viscous gel which acts as a cushion and an adherent between the denture plate and the gum tissue.
While these relatively simple formulations are effective in securing dentures within the oral cavity for a short period of time, generally more than one application of adhesive per day is necessary. This is, at best, inconvenient and therefore, most undesirable.
In recent years, there have been numerous improvements in the above-described simple denture adhesive formulations. For example, U.S. Pat. No. 2,978,812 discloses a substantially anhydrous denture fixative which includes an ethylene oxide polymer having a molecular weight between 500,000 and 5,000,000 in an amount preferably comprising at least 50% of the active fixative materials.
U.S. Pat. No. 3,511,791 teaches that copolymers of acrylamide and acrylic acid or homopolymers of acrylamide can form the principal adhesive component in a denture adherent to provide sustained adherence in use without swelling. Whenever a homopolymer of acrylamide, which is nonionic in character, is used, gum karaya is added to the formulation in order to provide a synergistic improvement in gel strength and adhesiveness.
U.S. Pat. No. 3,833,518 discloses an anhydrous denture adhesive which may include copolymers of acrylamide with vinyl quaternary salts, copolymers of acrylamide with vinyl and alkyl substituted vinyl pyridinium salts, O-lower alkyl-trimethylammonium chloride-substituted anhydroglucose polymer, in addition to a natural or synthetic anionic gum material such as sodium carboxymethylcellulose.
U.S. Pat. No. 4,280,936 discloses a denture adhesive comprising sodium carboxymethylcellulose and poly (ethylene oxide) homopolymer in a mineral oil base.
U.S. Pat. No. 4,373,036 discloses a denture fixative composition which includes hydroxypropylcellulose, in combination with partially neutralized polyacrylic acid, partially neutralized lower alkyl vinyl ether-maleic acid or anhydride copolymer and/or polyethylene oxide.
U.S. Pat. No. 4,514,528 is directed to a hydrophilic denture adhesive which consists of an admixture of mixed, partial salts of lower alkyl vinyl ether-maleic anhydride-type copolymers with either sodium carboxymethylcellulose or poly (ethylene oxide) homopolymer or both in a hydrophilic vehicle.
U.S. Pat. No. 4,518,721 discloses a denture adhesive which consists of sodium carboxymethylcellulose and poly (ethylene oxide) in a hydrophilic vehicle comprising certain polyethylene glycols and, optionally, glycerin.
While all of the above denture adhesives provide some improvement over simple formulations containing only finely powdered natural gums, it is generally recognized that no one product has yet been developed which can accommodate, over a long period of time, the many variations in temperatures, pH and mechanical agitation which are quite normal in the oral cavity.
It has now been found that the denture adhesive of this invention will provide superior adherent properties over prolonged periods of time and under unusually varied conditions, without the disadvantages characteristic of previously known products.